It has been considered that the human gets many gastritis, gastric ulcer and gastric cancer by Helicobacter pylori. A distinct direct cytotoxic factor causing destruction of gastric epithelial cells and irreversible cell death at the beginning of these diseases has not been specified. A factor changing pH environment and immunity reaction in the stomach, a factor adhering to gastric epithelial cells by Helicobacter pylori, or move properties of bacteria themselves has been indicated as a factor developing such diseases. However, it has been unclear hitherto that gastric mucosal destruction triggering gastritis, gastric ulcer and gastric cancer is injured in any process, or what is a direct responsible factor to the gastric mucosal destruction. The only is that vacuolating toxin having cytotoxicity is isolated, but it has week cytotoxic activity and reversible cytotoxic activity. As a fatal cytotoxic factor of a pathogenic factor, it has not been found in vivo and in vitro.
Many researchers estimate that Helicobacter pylori, as described in the above, in the environment stomach in vivo, secretes a direct cytotoxic factor for gastric mucosal cells. Considering the importance of diseases, all sequences of the gene is confirmed in 1996. However, in spite of the use of serum, it is impossible to isolate and identify the presumable toxin due to separation conditions, with difficult culture conditions and purification conditions and unfixed valuation systems of the toxin.
Problems to be Solved by the Invention
One problem is that responsible protein causing gastritis, gastric ulcer and gastric cancer by Helicobacter pylori infection is found, a mass production method of the toxic protein is established, new M toxin is identified, and diagnosis and screening method is established. Using these methods, it is desired that responsible toxin of a cytotoxic factor for gastric mucosal cells is controlled, and preventive and treating agents of gastritis, gastric ulcer, gastric cancer and the like are developed and a method for using the toxin is found.